Research On Routing Algorithm Of Data Center Network Based On SDN Architecture

With the development of the internet and the acceleration of the information process,a variety of internet applications and services are constantly emerging.As the core infrastructure of data center for these applications and services,its network traffic is growing rapidly,and how to allocate reasonable and efficient routing for these traffic has become one of the problems that are urgently needed to be addressed.Software Defined Network(SDN)and OpenFlow technology change the routing and forwarding methods of traditional network,the characteristic of separating the control and forwarding realizes the programmable control of the network,thus it has been used more and more widely in the data center network.This thesis researches the data center network routing algorithms and strategies based on SDN and OpenFlow technology,to make the traffic transmission of data center network reasonable and efficient.This thesis first analyzes the deficiencies of SDN-based data center network routing algorithm,which mainly involves two aspects: on the one hand,when develop routing strategies for the data flowing into the network according to the network real-time status,with the only consideration of a single network parameter,which can not reflect the real network state;on the other hand,existing rerouting algorithms don't consider the additional overhead of rerouting when re-scheduling the large flow on the congestion link.In view of these deficiencies,this thesis designs an initial routing algorithm and a dynamic rerouting algorithm based on scheduling overhead.The initial routing algorithm adopts both bandwidth and delayed parameters to measure the network link status,assigns different weight value for the two parameters,and calculates the comprehensive weight value of the link,then applies the Dijkstra algorithm to select proper route for the data flowing into the network.At the same time,the SDN controller monitors the real-time transmission situation of the network,after discovering the congestion link,it detects all large flows on the congestion link,the dynamic rerouting algorithm re-scheduling the large flow based on the scheduling overhead of the available paths until the network is no longer congested.Then,in order to implement the initial routing algorithm and the dynamic rerouting algorithm,the core function modules based on the Floodlight controller is proposed,including the information acquisition module,the path calculation module and the forwarding module.The modules are designed in detail,and all modules are programmed in the controller.Finally,an experimental simulation platform based on the Mininet and the Floodlight controller is built up,and the proposed initial routing algorithm and dynamic rerouting algorithm are simulated and verified.The experimental results show that the initial routing algorithm can improve the average network throughput,reduce the average transmission delay of data flows and the packet loss rate on a certain degree compared with the existing Equal Cost Multi-Path(ECMP)algorithm and Software-defined Hybrid Routing(SHR)algorithm.At the same time,the dynamic rerouting algorithm based on scheduling overhead can mitigate the congestion of the link,and reduce the network packet loss rate significantly.